Mexico’s Foreign Secretariat Responds to Texas: The Border on the Río Bravo Cannot Be Modified by a State Government

ByEmir Olivares

This article by Emir Olivares and La Jornada staff originally appeared in the October 30, 2026 edition of La Jornada, Mexico’s premier left wing daily newspaper.

In response to the unilateral decision of the Texas government to appropriate nine islands in the Río Bravo, the Secretariat of Foreign Affairs (SRE) warned that border limits cannot be modified by a state authority, since they are defined by an international treaty.

It warned that the Mexican government will follow up on any action in the area and reiterated its commitment to complying with the treaties that govern the shared border and to bilateral dialogue.

This was its response to the announcement made by Dawn Buckingham, the Texas Land Commissioner, that the nine islands –out of a total of 28 located in the Río Bravo– along its territory, between Laredo and McAllen, belong to Texas, which will allow the United States military to access them “in order to maintain operational security of the southern border and eliminate possible hiding places for drug traffickers.”

The official argued that the General Land Office, at the request of the Office of Customs and Border Protection, “confirmed” that the nine islands, whose ownership has been uncertain for years and which had not been claimed, belong to Texas, so they will be able to access them to carry out cleanup and patrol tasks.

Foreign Affairs Secretariat Invokes the Boundary Treaty

In a statement, the SRE made clear that the 1970 Boundary Treaty establishes that on the Río Bravo, the international boundary runs through the center of the river’s channel.

That boundary determines the sovereignty of the lands on both sides of the border.

Secretariat of Foreign Affairs

The Foreign Affairs Secretariat stressed that the International Boundary and Water Commission (CILA) is the body empowered by both governments to apply the treaty and determine on which side of the boundary each island lies. “No state authority has that power,” it specified.

It also warned that under the treaty, neither country may build works that, in the judgment of the CILA, could divert or obstruct the normal flow of the river.

In a statement, Buckingham acknowledged that no criminal activity has been confirmed on the nine islands, but said that “previous experience” demonstrated how border islands can be exploited by cartels and smugglers, although she did not give specific examples.